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Rehan, M, Miandad, R, Barakat, MA et al. (7 more authors) (2017) Effect of zeolite catalysts on pyrolysis liquid oil. International Biodeterioration & Biodegradation, 119. pp. 162-175. ISSN 0964-8305
https://doi.org/10.1016/j.ibiod.2016.11.015
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1
Effect of Zeolite Catalysts on Pyrolysis Liquid Oil 1
2 M. Rehan1,*, R. Miandad1,2, M.A. Barakat2, I.M.I. Ismail1, T. Almeelbi1, J. Gardy3, A. 3
Hassanpour3, M.Z. Khan4, A. Demirbas5, A.S. Nizami1 4 5
1Center of Excellence in Environmental Studies (CEES), King Abdulaziz University, Jeddah, Saudi 6 Arabia 7
2Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land 8 Agriculture, King Abdulaziz University, Jeddah, Saudi Arabia 9
3School of Chemical and Process Engineering (SCAPE), University of Leeds, LS2 9JT Leeds, UK 10 4Environmental Research Laboratory, Department of Chemistry, Aligarh Muslim University, Aligarh 11
Uttar Pradesh 202 002, India 12 5Faculty of Engineering, Department of Industrial Engineering, King Abdulaziz University, Jeddah, 13
Saudi Arabia 14 15
Abstract 16
17
The aim of this study was to determine the quality and applications of liquid oil produced by 18
catalytic pyrolysis of polystyrene (PS) plastic waste in comparison to thermal pyrolysis, using 19
a small pilot scale pyrolysis reactor. Thermal pyrolysis produced maximum liquid oil (80.8%) 20
with gases (13%) and char (6.2%), while catalytic pyrolysis using synthetic and natural zeolite 21
decreased the liquid oil yield (52%) with an increase in gases (17.7%) and char (30.1%) 22
production. The lower yield but improved quality of liquid oil through catalytic pyrolysis are 23
due to catalytic features such as microporous structure and high BET surface area. The liquid 24
oils, both from thermal and catalytic pyrolysis consist of around 99% aromatic hydrocarbons, 25
as further confirmed by GC-MS results. FT-IR analysis showed chemical bonding and 26
functional groups of mostly aromatic hydrocarbons, which is consistent with GC-MS results. 27
The produced liquid oils are suitable for energy generation and heating purposes after the 28
removal of acid, solid residues and contaminants. Further upgrading of liquid oil or blending 29
with diesel is required for its use as a transport fuel. 30
31
Keywords: Energy; Natural zeolites; Pyrolysis oil; Polystyrene (PS); Thermal pyrolysis; 32
Catalytic pyrolysis 33
*Corresponding author: E-mail: [email protected]; [email protected] 34
35 36
2
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 1. Introduction 64
65
The recent volatility in crude oil prices, shortages and unsustainable future supply, along with 66
environmental pollution generated especially by greenhouse gas emissions (GHG), all support 67
the development of alternatives to petroleum (Gardy et al., 2014; Demirbas et al., 2016). 68
Treaties like the Kyoto Protocol and Agenda 21 are also forcing fossil fuel-based economies 69
towards renewable energy-based economies (Ouda et al., 2016). Renewable energy sources 70
like wind, solar, geothermal, waste-to-energy (WTE), and biomass are attracting significant 71
attention to bridge the ever-increasing energy demand and supply gap (Lam et al., 2016). 72
Technological advancements, and cost effective techniques along with governmental 73
incentives are further increasing the growth of renewable energy sector (Nizami et al., 2016a, 74
b; Rathore et al., 2016). 75
76
The pyrolysis of plastic waste has emerged as an effective WTE technology (Table 1) as a 77
solution for plastic waste management and to generate energy (liquid oil) and value-added 78
LIST OF ACRONYMS AND ABBREVIATIONS AD: Anaerobic digestion BET: Brunauere-Emmete-Teller Btu: British thermal units EDS: Energy dispersive spectrometer FT-IR: Fourier transform infrared spectroscopy GC-MS: Gas chromatography-mass spectrophotometry GHG: Greenhouse gases HDPE: High density polyethylene HHV: Higher heating values HR-TEM: Higher resolution transmission electron microscopy ICP: Inductively coupled plasma KSA: Kingdom of Saudi Arabia LCA: life cycle assessments LDPE: Low density polyethylene MSW: Municipal solid waste O2: Oxygen PE: Polyethylene PP: Polypropylene PS: Polystyrene PTF: Plastic-to-fuel RDF: Refuse derived fuel SAED: Selected area electron diffraction SCAPE: School of Chemical and Process Engineering SEM: Scanning electron microscopy WTE: Waste-to-energy XRF: X-ray fluorescence
3
products (char and gases) (Sharma et al., 2014). The pyrolysis process involves thermal and 79
catalytic cracking of complex organic molecules into smaller molecules or short chain 80
hydrocarbons (Demirbas et al., 2015a; Kartal et al., 2011). The overall process mechanism is 81
complicated but mainly involves four steps: initiation, transfer, decomposition and termination 82
(Faravelli et al., 2001). Computer simulation studies consider hundreds of possible reactions 83
happening during the thermal cracking of substrate (Zhang et al., 2015). The process depends 84
on a series of factors including temperature, residence time, heating rates, feedstock 85
composition, presence of moisture or toxic elements and the use and types of catalysts 86
(Miskolczi et al., 2009, Miandad et al., 2016a, d, e). Similarly, a wide range of reactors are 87
employed e.g. fixed bed reactor, tube reactor, rotary kiln reactor and batch, semi-batch and 88
pyrex batch pyrolysis reactors (Syamsiro et al., 2014). 89
90
In catalytic pyrolysis, the plastic waste is depolymerized into an improved liquid oil at lower 91
temperature (~400 °C) in comparison to thermal pyrolysis, which is carried out in absence of 92
catalyst at higher temperature (~500 °C) (Miandad et al., 2016b). The liquid oil of thermal 93
pyrolysis is often unstable, low-grade, acid-corrosive, tarry and discoloured (Al-Salem et al., 94
2009; Hernandez et al., 2007). While the catalytic pyrolysis although decreases the liquid oil 95
yield, but increases its quality (Table 2). The selection of catalyst in catalytic pyrolysis depends 96
on the desired products such as liquid oil, char and gases and their quality (Walendziewski et 97
al., 2001). 98
99
Polystyrene (PS), polyethylene (PE) and polypropylene (PP) are the most used plastic types in 100
pyrolysis studies (Miandad et al., 2016a, b). Zeaiter (2014) obtained liquid oil from catalytic 101
pyrolysis of high density polyethylene (HDPE) waste using modified zeolites. The liquid oil 102
can be used in modified diesel engine vehicles after upgrading its gasoline range hydrocarbons 103
(C4 - C12) through refining and blending with conventional fuels. Furthermore, the liquid oil 104
can be used in heat generation and electricity production after removing the acid, solid residues, 105
and contaminants present in the oil (Demirbas et al., 2015a). The value-added products such as 106
styrene, benzene, toluene and other condensed aromatic hydrocarbons either cyclic or arenes 107
can also be obtained by distillation and refining process of liquid oil (Demirbas 2004; 108
Mohammed et al., 2015; Kobayashi et al., 2016). 109
110
4
In the Kingdom of Saudi Arabia (KSA) and in Gulf region, there exists no WTE facility to 111
convert the plastic waste into energy and value-added products. Similarly, the plastic waste and 112
natural zeolite have not been characterized for their potential role as an energy source and 113
catalyst in pyrolysis technology. This study aims to determine the quality of liquid oils 114
produced from thermal and catalytic pyrolysis using PS plastic waste in a small pilot scale 115
pyrolysis reactor. The effect of synthetic and natural zeolite catalysts were studied on the 116
fractions of liquid oils, gases and char in comparison to thermal pyrolysis. The quality of 117
produced liquid oil is evaluated based on its physico-chemical properties and energy contents. 118
119
1.1. Energy demands and plastic waste management in KSA 120
121
KSA is one of the world’s largest energy consuming countries due to its rapid population 122
growth (around 3.4% per year), urbanization (around 1.5% per year) and a rise in living 123
standards resulting from high economic growth. In 2013, the total energy consumption in KSA 124
surpassed 9 quadrillion British thermal units (Btu) making the country one of the 12 largest 125
primary energy consumers in the world (Nizami et al., 2015a, b). Currently, around 55% of 126
KSA energy demands are satisfied by petroleum and the remaining 45% by natural gas. The 127
KSA government wants to generate about half of the country’s energy (about 72 GW) from 128
renewable sources like nuclear (17.6 GW), solar (41 GW), wind (9 GW), geothermal (1 GW) 129
and WTE (3 GW) by 2032 (Nizami et al 2016b; Demirbas et al., 2015b). In the KSA, 15.3 130
million tons of municipal solid waste (MSW) was produced during 2014 (average 1.4 131
kg/capita/day) and it is estimated that figure will almost double to 30 million tons per year by 132
2033. Every year, around 6 million metric tons of plastic products are produced in KSA, and 133
thus it is the second largest waste stream of MSW (up to 17%) with total annual waste 134
generation of 2.7 million tons. All of the plastic waste, along with other MSW fractions, are 135
disposed in landfills or dumpsites. The plastic waste has detrimental environmental and 136
operational effects at landfill sites due to slow degradation rates and the presence of toxic dyes 137
and additives. Plastic waste is managed through different approaches, including reducing, 138
reusing, recycling and WTE. Conventional mechanical recycling techniques such as sorting, 139
grinding, washing and extrusion can recycle only 15-20% of all plastic waste. Beyond this 140
level, the plastics become contaminated with materials like soil, dirt, aluminium foil, food 141
waste and paper labels. Air and waterborne pollutants are emitted from uncontrolled plastic 142
combustion. In recent years, WTE technologies including gasification, pyrolysis, and refuse 143
5
derived fuel (RDF) and chemical recycling methods such as hydrolysis, methanolysis, and 144
glycolysis have been gaining significant attention. 145
146
2. Material and methods 147
148
2.1. Experimental setup 149
A small pilot scale pyrolysis reactor has been designed and used for thermal cracking of plastic 150
waste into liquid oil, gases and char (Figure 1). The reactor is a closed system to operate in the 151
absence of O2 and has a capacity to achieve up to 600 °C using desired heating rates. The 152
reactor is made of stainless steel and has a height of 360 mm with 310 mm diameter and a 153
capacity of 20 L (Table 3). There is also a pressure gauge connected with pyrolysis reactor to 154
monitor the pressure to switch off in case of excess pressure build-up. The system can work 155
both as a thermal or catalytic pyrolysis process. During the catalytic pyrolysis, the powder 156
catalyst was mixed with the feedstock in the pyrolysis reactor to study its effect on the final 157
products yield and quality. The sample was heated and melted in the reactor, producing organic 158
vapours. These vapours moved to a condenser unit and were converted into liquid oil by using 159
a chiller system attached to the condenser unit. ACDelco classic coolant was used in the chiller 160
to achieve maximum condensation of organic vapours for optimized liquid oil yields. The 161
condensed organic vapours (liquid oil) were collected from the oil collector assembly at the 162
bottom of the system. While the uncondensed products (gases) coming out from the same liquid 163
oil pipe were exhausted outside. The collected liquid oil was further analysed for its yield, 164
quality and potential applications. 165
166
2.2. Sample preparation and experimental scheme 167
PS disposable plates were used as plastic waste and treated in the pyrolysis process to produce 168
liquid oil, gases and char. 1 kg of PS sample was used for each experiment, including thermal 169
pyrolysis, catalytic pyrolysis with natural zeolite and synthetic zeolite catalysts. 100 g of both 170
natural and synthetic zeolite catalysts were used, which gives the catalyst to feedstock ratio of 171
1:10. This ratio was fixed based on the recently published research (Ateş et al., 2005; Lopez et 172
al., 2011). The synthetic zeolite catalyst (ZEOLYSTTM CBV 780 CY (1.6) Zeolite SDUSY 173
Extrudate) was purchased from Zeolyst International (Zeolyst, 2015) and used as received 174
without any further treatment. The chemical name of this synthetic zeolite catalyst is Zeolite 175
type SDUSY, hydrogen form, aluminium oxide and it has a specific gravity of greater than 1 176
6
with negligible solubility in water. The natural zeolite was extracted from the Harrat Ash-177
Shamah area located in the northwest of KSA (Nizami et al., 2016a). The samples were 178
collected for research purpose without requiring any specific permission from Government or 179
any other agencies. It also confirm that the field studies did not involve endangered or protected 180
species. This catalyst was simply milled to micron sized particles and used without any other 181
pre-treatment or surface modification. 182
183
The raw material (PS plastic waste) was prepared by cutting the disposable plates into small 184
pieces to achieve sample homogeneity. Each sample was heated from room temperature to 450 185
°C using heating rate of 10 °C/min and the reaction time was fixed to 75 min. The fractions of 186
liquid oil, gases and char were estimated on their weight basis. The produced liquid oil was 187
further characterized to study the effect of thermal and catalytic pyrolysis under presence of 188
synthetic and natural zeolite catalysts. The optimum conditions of 450 °C and 75 min for non-189
catalytic pyrolysis process was first determined by TGA (Mettler Toledo TGA/SDTA851) 190
analysis of the PS plastic sample under controlled conditions. The analysis was carried out by 191
heating 10 µg of PS sample at the rate of 10 °C per min from 25-900 °C under nitrogen flow 192
at a constant rate of 50 ml/min. The detailed experiments on effect of temperature and reaction 193
time on pyrolysis products and choosing optimum conditions as well as TGA results and 194
analysis have been published earlier by the authors (Miandad et al., 2016d). 195
196
2.3. Analytical characterization 197
The characterization of natural zeolite was carried out at the School of Chemical and Process 198
Engineering (SCAPE), University of Leeds, UK and detailed results have been published 199
earlier by the authors (Nizami et al., 2016a). The Brunauere-Emmete-Teller (BET) surface 200
area, pore size and volume of natural zeolite catalyst were analysed by using Micromeritics 201
TriStar 3000 (UK) surface analyser and the experimental details are provided in earlier study 202
(Nizami et al., 2016a). The particle size and morphology distribution of natural zeolites was 203
examined by Hitachi scanning electron microscopy (SEM). The elemental analysis of natural 204
zeolite was carried out by energy dispersive spectrometer (EDS) attached with SEM. A 205
homogeneous suspension of sample was prepared by mixing zeolite powder in acetone using 206
ultrasonic batch. Few drops of this homogenous diluted sample was then added on SEM stubs 207
and the stubs were dried and transferred to a cleaning zone. UV-Ozone radiation unit was used 208
at pressure 1 Pa for 10 min to remove any possible contamination. The cleaned samples were 209
7
finally installed in SEM and images at different magnifications and EDS were collected for 210
detailed analysis. The produced liquid oils from thermal and catalytic pyrolysis with natural 211
and synthetic zeolite catalysts were further characterized by a number of analytical techniques. 212
The chemical structure and the functional groups present in PS plastic raw material and 213
produced liquid oil samples were studied by Fourier transform infrared spectroscopy (FT-IR), 214
Perkin Elmer's, UK. A minimum of 32 scans were performed at average signal of IR with a 215
resolution 4 cm-1 in the ranges of 500-4000 cm-1. 216
217
Gas chromatography coupled with mass spectrophotometry (GC-MS) of Hawlett-Packard HP 218
7890 was used to analyse the chemical composition of produced liquid oils by both thermal 219
and catalytic pyrolysis. The produced liquid oils were mixed with polar solvent 220
dichloromethane and injected to GC-MS for analysis. The GC-MS system used a 30 m long 221
with 0.25 mm diameter capillary column coated with 0.25 µm thick film of 5% phenyl-222
methypolysiloxane and worked with a 5975 quadrupole detector. The initial temperature of the 223
oven was kept at 50 °C for 2 min and then increased to 290 °C at the rate of 5 °C per min at 224
holding rate of 10 min. The ion source and transfer line temperatures were kept at 230 °C and 225
300 °C respectively. The GC-MS was operated in full scan mode between m/z 33-533 using 226
splitless injection function at 290 °C and solvent interval of 3 min. The obtained peaks based 227
on their retention times were matched with standard compound peaks in NIST08s mass spectral 228
data library. The percentage fractions of different hydrocarbon and other compounds present 229
in the liquid oil samples were determined by total ion chromatogram peak areas using the 230
software. The energy contents, in terms of higher heating values (HHV) of the PS plastic raw 231
material and produced liquid oil, were analysed by bomb calorimeter (Parr 6200 Calorimeter, 232
US) based on the ASTM D 240 method. 233
234
The characteristics of pyrolysis liquid oils were determined by relevant techniques based on 235
standard ASTM methods. The viscosities of the liquid oil were measured by a Discovery 236
Hybrid Rheometer (HRI from TA instruments) with a 40 mm parallel plates geometry. A small 237
amount of the liquid oil sample was placed on the bottom horizontal plate. The upper 40 mm 238
plate was lowered at a controlled rate so that the sample was sandwiched between the two 239
plates. The temperature was set to 40 °C and the shear rate range was set between 1-500 1/s. 240
The rheometer was first calibrated using viscosity standard liquid followed by actual liquid 241
viscosity measurements. Flash point of produced liquid oil was determined by Automatic 242
8
Pensky-Martens Closed Tester (Koehler, US) based on the ASTM D 93 method. For pour point, 243
AWD-12 Pour Point Tester was used with temperature of -10 °C for one tank (left tank) and 244
the temperature of -56 °C for other tank (right tank). The sample was poured in the sample tube 245
up to the mark. The sample was first put in the left tank till the temperature reduces to 0 °C and 246
then transferred to the tank on the right side. The sample tube was taken out periodically from 247
the tank after every 2 °C decrease in temperature to observe the flow by holding the tube 248
horizontally for 4 seconds. This process was continued until the pour point was reached. For 249
density measurement, a portable density meter (DMA 35 from Anton Paar) was used, which 250
was first calibrated with distilled water and then rinsed with acetone and allowed to dry 251
between each sample, before taking the next measurements. 252
253
3. Results and discussion 254
255
3.1. Characteristics of KSA’s natural zeolite 256
The SEM images revealed that mostly spherical shaped particles were between 50-200 nm size-257
range (Figure 2). However, some larger grains with irregular morphology were also observed 258
in 0.5-1 nm size range. The BET surface area, pore size and volume of natural zeolite were 259
found to be 4.3 m2/g, 18.7 Å and 0.02 cc/g respectively (Nizami et al., 2016a). The microporous 260
nature of zeolite plays a vital role in thermal cracking reactions by adsorbing selective larger 261
hydrocarbon chain molecules and other impurities to produce improved liquid oil. The surface 262
area and pore volume of the catalyst can be increased significantly by chemical treatment such 263
as acid leaching or thermal activation that will further enhance its catalytic functions 264
(Sriningsih et al., 2014). Similarly, the impurities present in natural zeolite catalyst can also be 265
removed by chemical or thermal treatment (Syamsiro et al., 2014). To study the in-depth 266
microporous structural features of natural zeolites, samples must be milled to below 100 nm 267
size range. Higher resolution transmission electron microscopy (HR-TEM) analysis can be 268
used to obtain detailed structural features including particle size, clear morphology, 269
crystallographic phases from HR-TEM images, atomic fringes, selected area electron 270
diffraction (SAED) and EDS analysis (Rehan et al., 2011, 2015). This would be the subject of 271
our future studies. 272
273
Natural zeolites are alumina-silicates complex structured minerals containing a number of earth 274
metals such as Na, Ca, K, Mg, and Fe (Nizami et al., 2016a). The energy dispersive spectra 275
9
(EDS) were taken from different regions of the SEM image, which showed some differences 276
in the weight percentage composition, and spectrum 4 is presented in figure 3. The weight 277
percentage of major components were found to be O (57.2%), Si (26.7%) and Al (7.0%). The 278
minor components included Na (2.2%), Mg (0.6%), S (0.4), K (2.7%), Ca (0.5%), Ti (0.2%) 279
and Fe (2.5%) (Figure 3). The elemental analysis of compounds like zeolites are generally 280
performed by SEM-EDS with enough degree of accuracy, however the results obtained do vary 281
from sample to sample. This is because the spectrum is taken from one single point that may 282
not always be a true representative of the whole sample. However, the most accurate 283
quantitative elemental analysis including all major and minor components including impurities 284
can be achieved by inductively coupled plasma (ICP) and X-ray fluorescence (XRF). 285
286
3.2. Analysis of pyrolysis products yield 287
Figure 4 and table 4 show the results for amounts of liquid oil, gases and char produced from 288
thermal and catalytic experiments. Thermal pyrolysis produced maximum liquid oil (80.8%) 289
with gases (13%) and char (6.2%), while catalytic pyrolysis decreased the liquid oil yields to 290
54% and 50% from natural zeolite and synthetic zeolite respectively. Natural zeolite having 291
BET surface area of 4.3 m2/g produced 54% liquid oil yield, while synthetic zeolite with surface 292
area of 780 m2/g produced 50% liquid oil yield. The char produced from catalytic pyrolysis, 293
32.8% with natural zeolite and 27.4% with synthetic zeolite, was higher than 6.2% from 294
thermal pyrolysis. Similarly, gases production was at a maximum with synthetic zeolite 22.6% 295
and 12.8% with natural zeolite as compared to 13% from thermal pyrolysis (Figure 4). Lopez 296
et al. (2012) and Syamsiro et al. (2014) also reported similar products yield trends that use of 297
the catalyst decreased overall liquid oil yield with an increase in char and gases production. 298
299
The lowest liquid oil yield and highest gas production in catalytic pyrolysis with synthetic 300
zeolite can be due to its microporous structure and high BET surface area (Figure 5). Seo et al. 301
(2003) also reported that use of microporous catalyst with high BET surface area will lead to 302
an increase in gas and decrease in liquid oil yields. The natural zeolite has lower BET surface 303
area and microporous structure as compared to synthetic zeolite, thus increasing the char 304
production. Lopez et al. (2011) reported the similar results by using ZSM-5 and red mud 305
catalysts having BET surface area of 412 m2/g and 27.1 m2/g respectively. Moreover, catalysts 306
with higher acidity increase the cracking process that also increases the gases production and 307
decreases liquid oil yield (Sriningsih et al., 2014). The synthetic catalyst used in the present 308
10
study was more acidic than natural zeolite, thus it increased the gases production with a 309
decrease in liquid oil (Figure 4 & 5). 310
311
3.3. Analysis of pyrolysis liquid oil quality 312
The chemical composition of PS plastic raw material and pyrolysis liquid oils were studied by 313
using FT-IR spectra and are drawn on the same graph (Figure 6). This technique identifies the 314
chemical bonds in a molecule by producing an infrared absorption spectrum, leading to 315
identification of functional groups. Many clear peaks were generated, ranging from 697-3070 316
cm-1. The FT-IR spectra for all three pyrolytic liquid oils are very similar for peak positions 317
except for minor differences in some peak intensities possibly due to the variations in 318
percentage compositions of different aromatic hydrocarbons found in these liquid oils (Figure 319
6). The FT-IR peaks were characterized and matched with the standard characteristic IR 320
absorption peaks given in Orgchem (2015). The two strongest sharp peaks found at 697 and 321
775 cm-1, attributed to the =C-H out of plane bending vibrations for mono-substituted benzene 322
rings. Another medium peak found at 1490 cm-1 falls within the 1500-1400 range 323
corresponding to C=C stretch for substituted aromatic hydrocarbons. One weak peak at 1450 324
cm-1 can be assigned to C-H bend in alkanes. Two sharp peaks appeared at 905 and 989 cm-1 325
are corresponding to =C-H bend in alkenes. Many weak absorption peaks found at the higher 326
frequency range from 2800-3100 cm-1 and were at 2850, 2920, 2940 cm-1 and 3020, 3030, 3070 327
cm-1 fall within standard ranges of 3100-3000 for sp3 C-H stretch in alkanes and 3100-3000 328
cm-1 for sp2 C-H stretch in aromatics, respectively (Figure 6). These FT-IR results presented 329
strong evidence that aromatic hydrocarbons were the major components found in the liquid oils 330
produced from both thermal and catalytic pyrolysis. 331
332
The FT-IR analysis of the PS plastic raw material was also carried out and its spectrum is 333
shown in figure 6. Most of the peaks found for raw material matched closely with the FT-IR 334
peaks of pyrolytic liquid oils. The minor differences in the peak frequencies and intensities in 335
raw material to liquid oil samples were possibly due to different phases and degree of 336
crystallinity of styrene, some impurities or additives present in the plastic feedstock. The other 337
strong peak at 533 cm-1 might be attributed to the =C-H OOP of mono-substituted benzene 338
ring. This absorption band also observed for the native styrene (raw material), but it has not 339
been previously reported in the literature (Pavia et al., 2008). These results (Figure 6) are also 340
consistent with other related studies, where it is reported that the liquid oil obtained from PS 341
11
plastic feedstock mainly produce aromatic hydrocarbons with paraffins (alkanes), olefins 342
(alkenes) and naphthenes (cycloalkanes) in minor quantities (Siddiqui et al., 2009; Lee et al., 343
2002; Ramli et al., 2011; Kim et al., 2002). 344
345
The GC-MS results also showed the presence of aromatic hydrocarbons as being dominant 346
compounds in liquid oils from both thermal and catalytic pyrolysis (Figure 7). In thermal 347
pyrolysis, styrene was the main compound (48.3%) with ethylbenzene (21.2%), toluene 348
(25.6%) and benzo(b)triphenylene (1.6%). In catalytic pyrolysis with natural zeolite, styrene 349
was also the major compound (60.8%) with methylstyrene (10.7%), azulene (4.8%), 1H-indane 350
(2.5%) and ethylbenzene (1.3%) (Figure 7). In catalytic pyrolysis with synthetic zeolite, the 351
following compounds were found in descending concentrations: alpha-methylstyrene (38.4%), 352
benzene (16.3%), styrene (15.8%), ethylbenzene (9.9%), isopropylbenzene (8.1%), 353
propenylbenzene (4.2%) and propyl benzene (3.5%) (Figure 7). These findings are in 354
agreement with other studies that observed the chemical composition of liquid oil produced 355
from MPW mainly consists of aromatic hydrocarbons with some paraffins (alkanes: CnH2n+2), 356
olefins (alkenes: CnH2n), and naphthenes (cycloalkanes) (Shah and Jan, 2014; Ukei et al., 357
2000). Moreover, the chemical composition of liquid oil depends on plastic types and various 358
process conditions, including temperature reaction time, and type and amount of catalyst used. 359
For example, benzene, styrene, ethylbenzene, toluene, g-methylstyrene and indane derivate are 360
the major compounds reported by many researchers (Shah and Jan, 2014; Ukei et al., 2000; 361
Lee et al., 2002). Lee et al. (2002) reported that liquid oil produced from catalytic degradation 362
of PS consists more than 99% of aromatic compounds with minor quantities of n-paraffin 363
(0.02%), iso-paraffin (0.1%), olefins (0.03%) and naphthenes (0.1%), which is in agreement 364
with our findings (Figure 7). Similarly, the liquid oil produced by Ramli et al. (2011) from 365
thermal and catalytic pyrolysis contained 80% and 85-90% of aromatic hydrocarbons 366
respectively. The high ratio of aromatic compounds found in the pyrolytic liquid oil from 367
thermal and catalytic degradation of PS is due to the high stability of these compounds, which 368
inhibit the further cracking or hydrogenation into paraffin and olefins (Saptoadi et al., 2015). 369
The GC-MS results revealed that pyrolysis liquid oils mainly consist of aromatic hydrocarbons, 370
which is in agreement with FT-IR results (Figure 6). 371
372
In both thermal and catalytic pyrolysis of PS, styrene was the main compound found in 373
produced liquid oils with some other aromatic compounds such as ethylbenzene, toluene and 374
12
methylstyrene. Styrene production in thermal pyrolysis oil was 48.3%, while in catalytic 375
pyrolysis oil there was an increase in the production of styrene (60.8%) using natural zeolite. 376
The styrene with synthetic zeolite however decreased down to 15.8% with an increase in its 377
derivatives alpha-methylstyrene (38.4%). Many researchers reported similar results that 378
styrene, ethylbenzene, toluene and methylstyrene were the major compounds from the 379
degradation of PS (Aguado et al., 2003; Artetxe et al., 2015; Bartoli et al., 2015). According to 380
Onwaduili et al. (2009), there is no direct production of toluene and ethylbenzene from the 381
plastic waste raw material and they may be produced by the reaction of styrene itself. 382
Moreover, production of styrene initially increases with an increase of temperature but further 383
increase in temperature to above 500 °C showed a declining trend in the styrene production. 384
Beyond 500 °C, it is reported that styrene production decreases with the increase in the 385
production of toluene and ethylbenzene, which shows further decomposition of styrene at high 386
temperature (Demirbas, 2004; Onwudili et al., 2009). 387
388
It has been reported by many researchers that increase in pyrolysis temperature and reaction 389
time decreases the production of styrene with the increase of toluene and ethylbenzene. (Agudo 390
et al., 2003; Artetxe et al., 2015; Bartoli et al., 2015). This increase in the production of 391
ethylbenzene, toluene and methylstyrene is attributed to the hydrogenation of styrene at high 392
temperature due to secondary reactions (Ukei et al., 2000). In addition increase in reactor 393
pressure also decreases the production of styrene with the increase in toluene and ethylbenzene 394
which is due to the hydrogenation of styrene into its derivate (Shah and Jan, 2014). Overall 395
decrease in styrene production with the increase in ethylbenzene, toluene, methylstyrene or 396
production of high molecular weight hydrocarbon (benzene, 3-butynyl) either may be due to 397
further cracking of styrene via hydrogenation (Lee et al., 2002) or recombination of styrene to 398
higher molecular weight via H-abstraction followed by cyclization (Hu and Li, 2007). Overall 399
secondary reactions are responsible for the decrease in the production of styrene (Karaduman, 400
2002). 401
402
Styrene production is also effected by the selection of catalyst. Styrene production is higher in 403
catalytic pyrolysis as compared to thermal pyrolysis when solid base catalyst was used (Shah 404
and Jan, 2014). Ukei et al. (2000) used solid base catalyst (BaO) for the degradation of PS and 405
achieved maximum styrene recovery. Adnan et al. (2014) used Cu base catalyst and achieved 406
up to 60% of styrene recovery. However use of solid acid catalyst decreases the production of 407
13
styrene and increase the production of ethylbenzene, toluene and methylstyrene. Audisio et al. 408
(1990) reported the very low production of styrene (below 5% weight) by using silica alumina, 409
REY or HY zeolite at 350 °C. Lee et al. (2003) reported that use of solid acid catalyst decreases 410
the production of styrene as compare to thermal pyrolysis. Thermal pyrolysis achieved 52.2% 411
of styrene recovery however it decreases with the use of solid acid catalyst such as NZ (50.8%), 412
HNZ (48.1%), HSCLZ (47.7%) and SA (36.1%). The decrease in styrene production is may be 413
due to high acidity of catalyst which increases the rate of secondary reactions. This is possibly 414
the reason for a decrease in styrene production in liquid oil from synthetic zeolite catalytic 415
pyrolysis in this study (Figure 6). Since the structure of the synthetic zeolite would be more 416
pure and highly crystalline than natural zeolite, it is therefore probably more acidic in nature 417
as well. This observation is in line with the work of Nizami et al. (2016a) and Miandad et al. 418
(2016a, b). 419
420
The energy content is one of the most important characteristics of any fuel in its applications 421
and it can be characterised by its HHV. The higher the HHV value of a fuel, the higher the 422
energy content of the fuel, meaning the required performance can be achieved with less fuel 423
quantity (Saptoadi et al., 2015). In this study, the average HHV of PS plastic raw material, 424
liquid oils produced from thermal and catalytic pyrolysis with natural and synthetic zeolite 425
catalysts were found to be 39.3, 41.6, 41.7 and 40.6 MJ/kg respectively (Table 5). The slightly 426
lower HHV of raw material to liquid oils can be due to its solid phase form. Similarly, the 427
minute difference in HHV of oil from synthetic zeolite catalyst to other oils may be due to the 428
presence of ash or catalyst particulates in final product. These results are in agreement with 429
many other studies such as Syamsiro et al. (2014) that reported the HHV of 36.3 MJ/kg for 430
liquid oil produced from pyrolysis of PS plastic raw material at 450 °C. Lopez et al. (2011) 431
reported a HHV of 41.5 MJ/kg for liquid oil produced from pyrolysis of packaging plastic 432
waste at 440 °C. Moreover, the HHV of pyrolytic liquid oils are very close to HHV (43.1 433
MJ/kg) of conventional diesel (Table 5), which further affirms its suitability to be used for 434
energy production. Some studies have also suggested that pyrolytic oil, having slightly lower 435
HHV then diesel, can be suitably utilized as it is as a fuel or after mixing it with kerosene oil 436
(Saptoadi et al., 2015). 437
438
The thermal pyrolysis oil was further characterized for various parameters such as dynamic 439
viscosity, kinematic viscosity, density, pour point and flash point and compared with reported 440
14
conventional diesel values (Table 6). The dynamic and kinematic viscosity was found to be 1.8 441
mPa.s and 1.9 cSt, which are comparable to 1-4.1 mPa.s and 2.0-5.0 cSt ranges of conventional 442
diesel respectively. The density was found to be 0.9 g/m3 which is also close to reported density 443
range of 0.8-0.9 g/m3 for conventional diesel. The flash point was found to be 30.2 °C, which 444
is below the conventional diesel range of 55-60 °C. One of the possible reason for this lower 445
flash point could be that pyrolysis liquid oil mainly consist of aromatic hydrocarbons. 446
447
3.4. Potential applications of pyrolysis technology in KSA and other developing countries 448
There is a huge potential applications for pyrolysis technology in KSA and other developing 449
countries of Asia, Africa and Latin America. The liquid oil produced by pyrolysis process is 450
suitable to be used as a feedstock for value-added chemicals production, energy generation, 451
transport fuel and heating purposes (Islam et al., 2010; Ouda et al., 2016; Rehan et al., 2016). 452
The consumption and generation of plastic waste in these countries have increased to an 453
alarming rates (Ouda et al., 2016). For instance, in KSA, around 6 million metric tons of plastic 454
products are produced every year and therefore, it is the second largest waste category of MSW 455
with total generation of 2.7 million tons per year. 456
457
Rehan et al. (2016) have recently described a case study of Makkah on the amounts of liquid 458
oil that can be generated from all the plastic waste produced in Makkah city together with 459
details on achieving economic savings and other environmental benefits. Rehan et al. (2016) 460
estimated that around 87.91 MW of electricity can be produced along with global warming 461
potential savings of 199.7 thousand Mt.CO2 eq. in Makkah city by utilizing all of the plastic 462
waste in the pyrolysis process. A total economic savings of 297.52 million SAR or 79.33 463
million USD will be achieved from carbon credits, landfill diversion and electricity production 464
from pyrolytic liquid oil. Moreover, the pyrolysis has an advantage over other WTE 465
technologies including incineration and plasma arc gasification due to less annual capital cost 466
($17-25/ton) and net operational cost ($2-3/ton) (Table 1). 467
468
The quality of liquid oil produced needs to be improved further in terms of removing some of 469
the heavy hydrocarbons and impurities (Figure 8). Many studies have been recently published 470
on improving the pyrolytic liquid oil quality by various methods such as filtration, chemical 471
treatment, by blending it with conventional fuels and distillation and refining (Islam et al., 472
2010; Mohebali and Ball, 2016; Chong and Hochgreb, 2015). Pyrolysis has also been reported 473
15
to be an effective way to recover the styrene from PS plastic. Several researchers have reported 474
the production of styrene, ethylene benzene and toluene with some other styrene monomers 475
from the thermal degradation of PS plastic (Jung et al., 2013; Artetxe et al., 2015). Recovered 476
styrene can be used as feedstock in various industries for PS polymerization (Achilias et al., 477
2007). Biodegradable plastic i.e. polyhydroxyalkanoate can also be produced from pyrolytic 478
liquid oil produced from thermal degradation of PS plastic wastes (Nikodinovic-Runic et al., 479
2011). 480
481
The oil produced in this study was found to have similar chemical composition and HHV values 482
as conventional diesel (Table 7). Thus produced liquid oil has the potential to be used as 483
alternative of conventional diesel. However produced liquid oil should be upgraded or blended 484
with conventional diesel as it contains high aromatic content. The high percentage of styrene 485
found in liquid oils from both thermal and catalytic pyrolysis could be used as valuable 486
chemicals for improving the octane number of petrol fuel produced from crude oil by blending 487
them in different proportions. The octane number of petrol fuel mainly depends on their 488
hydrocarbon composition such as n-paraffins and olefins are less desirable compared to iso-489
alkanes, naphthenic and aromatic compounds. Furthermore, higher octane number is favoured 490
for prevention of early ignition which leads to cylinder knock (Andras et al., 2007; Corma 491
1996; Madon 1991). 492
493
Several studies have reported the mixing and blending of pyrolytic oil with conventional fuel 494
in different ratios to further improve its quality (Sharuddin et al., 2016; Li et al., 2016; Kumara 495
et al., 2013). For example, the produced liquid oil was blended with the diesel oil with different 496
ratios i.e. 5%, 10%, 20%, 30%, 40% and 45% (Frigo et al., 2014; Nileshkumar et al., 2015; 497
Lee et al., 2015). Wongkhorsub and Chindaprasert (2013) directly injected the pyrolytic liquid 498
oil produced from wastes tires and wastes plastic into diesel engine. All aforementioned studies 499
reported the successful use of pyrolytic liquid oil for energy generation. Engine performance 500
and exhaust emissions were also examined with the use of pyrolytic liquid oil. The results 501
concluded that among all the used ratios 20/80% (pyrolytic liquid oil/conventional diesel) ratio 502
showed similar performance as conventional diesel. Lee et al. (2015) reported 13% decrease in 503
engine performance at 2450 rpm while it reaches to 17% at 3500 rpm with 20/80% ratio. 504
Nileshkumar et al. (2015) also recommended the same ratio for the better performance of 505
engine. However fuel consumption increased with the increase in blending ratio due to slightly 506
16
lower calorific value of pyrolytic liquid oil (Cleetus et al., 2013). In addition exhaust emissions 507
also increased as blending ratios increased reaching to its maximum at 50/50% blending ratio. 508
Nileshkumar et al. (2015) reported that at 20/80% blending ratio, COx and NOx emissions 509
were (0.5 and 0.7 g/km) and (0.3 and 0.4 g/km) for low and full load respectively. However for 510
conventional diesel the reported emissions were 0.5 and 0.7 g/km for COx while, 0.3 and 0.4 511
g/km for NOx respectively. More comprehensive studies are required to fully understand the 512
transformation of pyrolytic liquid oil into pure clean transportation fuel and its effect on 513
internal combustion engine performance, stability and structural damage as well as the type 514
and impact of gases emissions. 515
516
3.5. Future perspective 517
There is much scope in the optimization of the pyrolysis process on a large scale by detailed 518
investigations of the effect of various process parameters, feedstock type, and type of catalyst 519
used. Most of the pyrolysis plants at pilot and commercial scale use synthetic catalysts 520
intensively in order to improve the yield and quality of liquid oil and to overall optimize the 521
pyrolysis process. Despite the recent advancements in pyrolysis technology, several issues and 522
scope for further process optimization still remain. For example, the use of synthetic catalysts 523
in pyrolysis technology is making the overall process more energy intensive and economically 524
expensive. In such scenario, a significant research is underway on exploring new and cheap 525
catalysts, reusing catalyst, using natural minerals as catalysts, and using of catalysts in less 526
quantities. Another area of further research would be to study the activation of produced char 527
with steam and other appropriate gases and to study its various potential applications such as 528
removal of heavy metals and other toxic contaminants from wastewater and soil (Aktaş and 529
Çeçen, 2007; Qin et al., 2013). Jindaporn and Lertsatitthanakorn et al. (2014) reported that the 530
char produced from pyrolysis of HDPE waste has a calorific value of 4,500 cal/g and its surface 531
area and volume increased by thermal activation at 900 °C for 3 hours. 532
533
Natural zeolite catalysts are used successfully in the pyrolysis process; however, there is scope 534
for further improvement in their catalytic performance by removing some of the impurities 535
present and by increasing their surface area and volume. This surface and structural 536
modifications can be carried out by acid leaching, and thermal treatment and wet impregnation 537
(Nizami et al., 2016a). Syamsiro et al. (2014) reported that the natural zeolite’s catalytic 538
performance was improved by removing the volatile impurities through thermal treatment at 539
17
500 °C for 3 hours. Similarly, the catalytic performance of natural zeolites was improved by 540
removing impurities and increasing the overall catalyst acidity via HCl leaching process 541
(Sriningsih et al., 2014). Wet impregnation method is an important technique widely used to 542
modify and generate heterogeneous catalysts (Adnan et al., 2014). The life cycle assessments 543
(LCA) of feedstock, products and process are also recommended (Nizami, 2015; Shahzad et 544
al., 2015; Singh et al., 2010; Nizami and Ismail, 2013) that are very important to fully 545
understand the economic, technical and environmental aspects of pyrolysis technology before 546
its installation at a commercial scale. 547
548
4. Conclusions 549
550
The GC-MS results showed that around 99% aromatic hydrocarbons were found in liquid oils 551
produced by both thermal and catalytic pyrolysis. In thermal pyrolysis oil, the major 552
compounds were styrene (48.3%), ethylbenzene (21.2%), toluene (25.6%) and benzo (b) 553
triphenylene (1.6%). In catalytic pyrolysis with natural zeolite, the major compounds were 554
styrene (60.8%), methylstyrene (10.7%), azulene (4.8%), 1H-indane (2.5%) and ethylbenzene 555
(1.3%), while, in catalytic pyrolysis with synthetic zeolite, the major compounds were alpha-556
methylstyrene (38.4%), styrene (15.8%), benzene (16.3%), ethylbenzene (9.9%), and 557
isopropylbenzene (8.1%). The FT-IR analysis also revealed chemical bonding and functional 558
groups of mostly aromatic hydrocarbons found in all samples, which is in agreement with GC-559
MS results. The average HHV of PS plastic feedstock, liquid oil produced from thermal and 560
catalytic pyrolysis with natural zeolites and synthetic zeolites were found to be 39.3, 41.6, 41.7 561
and 40.6 MJ/kg respectively. The produced liquid oils are suitable for heating and energy 562
generation applications after post-treatment. However, the high percentage of aromatic 563
compounds (up to 99%) in liquid oil make it less suitable as a transportation fuel until it further 564
goes through refining stages including blending with diesel. This will upgrade the liquid oil to 565
gasoline range hydrocarbons (C4 - C12). 566
567
Acknowledgments 568
Dr Mohammad Rehan and Dr Abdul-Sattar Nizami acknowledge the Center of Excellence in 569
Environmental Studies (CEES), King Abdulaziz University (KAU), Jeddah, KSA and Ministry 570
of Education, KSA for financial support under Grant No. 1/S/1433. Authors are also thankful 571
18
to Deanship of Scientific Research (DSR) at KAU for their financial and technical support to 572
CEES. 573
574
References 575
576
Adnan, R., Shah, J., Jan, M.R., 2014. Polystyrene degradation studies using Cu supported catalysts. J. 577
Anal. Appl. Pyrolysis 109, 196-204. 578
579
Aguado, R., Olazar, M., Gaisán, B., Prieto, R., Bilbao, J., 2003. Kinetics of polystyrene pyrolysis in a 580
conical spouted bed reactor. Chem. Eng. J. 92, 9-99. 581
582
Al -Salem, S.M., Lettieri, P., Baeyens, J., 2009. Recycling and recovery routes of plastic solid waste 583
(PSW): A review. Waste Manage. 29, 2625-2643. 584
585
Andras, A., Miskolczi, N., Bartha, L., 2007. Petrochemical feedstock by thermal cracking of plastic 586
waste. J. Anal. Appl. Pyrolysis 79, 409-414. 587
588
Aktaş, Ö., Çeçen, F., 2007. Bioregeneration of activated carbon: a review. Int. Biodeterior. Biodegrad. 589
59, 257-272. 590
591
Artetxe, M., Lopez, G., Amutio, M., Barbarias, I., Arregi, A., Aguado, R., Bilbao, J., Olazar, M., 2015. 592
Styrene recovery from polystyrene by flash pyrolysis in a conical spouted bed reactor. Waste Manage. 593
45, 126-33. 594
595
Ateş, F., Pütün, A.E., Pütün, E., 2005. Fixed bed pyrolysis of Euphorbia rigida with different catalysts. 596
Energ. Convers. Manage. 46, 421-432. 597
598
Audisio, G., Bertini, F., Beltrame, P.L., Carniti, P., 1990. Catalytic degradation of polymers: Part III 599
degradation of polystyrene. Polym. Degrad. Stab. 29, 191-200. 600
601
Bartoli, M., Rosi, L., Frediani, M., Undri, A., Frediani, P., 2015. Depolymerization of polystyrene at 602
reduced pressure through a microwave assisted pyrolysis. J. Anal. Appl. Pyrolysis 113, 281-287. 603
604
Chong, C.T., Hochgreb, S., 2015. Spray and combustion characteristics of biodiesel: Non-reacting and 605
reacting. Int. Biodeterior. Biodegrad. 102, 353-360. 606
607
19
Cleetus, C., Thomas, S., Varghese, S., 2013. Synthesis of petroleum-based fuel from waste plastics and 608
performance analysis in a CI engine. J. Energy. Article ID 608797, 2013, 1-10. 609
610
Corma, A., 1996. Transformation of hydrocarbons on zeolite catalysts. Catal. Lett. 22, 33-52. 611
612
Demirbas, A., 2004. Pyrolysis of municipal plastic wastes for recovery of gasoline range hydrocarbons. 613
J. Anal. Appl. Pyrolysis 72, 97-102. 614
615
Demirbas, A., Al-Sasi, B.O., Nizami, A.S., 2016. Recent volatility in the price of crude oil. Energy 616
Sources Part A. doi:10.1080/15567249.2016.1153751. 617
618
Demirbas, A., Balubaid, M.A., Kabli, M., Ahmad, W., 2015a. Diesel fuel from waste lubricating oil by 619
pyrolytic distillation. Pet. Sci. Technol. 33, 129-138. 620
621
Demirbas, A., Alsulami, H., Nizami, A.S., 2015b. The natural gas potential of Saudi Arabia. Energy 622
Sources, Part A 38, 2635-2642. 623
624
Eqani, S.A.M.A.S., Khalid, R., Bostan, N., Saqib, Z., Mohmand, J., Rehan, M., Ali, N., Katsoyiannis, 625
I.A., Shen, H., 2016. Human lead (Pb) exposure via dust from different land use settings of Pakistan: 626
A case study from two urban mountainous cities. Chemosphere 155, 259-265. 627
628
Faravelli, T., Pinciroli, M., Pisano, F., Bozzano, G., Dente, M., Ranzi, E., 2001. Thermal degradation 629
of polystyrene. J. Anal. Appl. Pyrolysis 60, 103-121. 630
631
Frigo, S., Seggiani, M., Puccini, M., Vitolo, S., 2014. Liquid fuel production from waste tyre pyrolysis 632
and its utilisation in a diesel engine. Fuel 116, 399-408. 633
634
Gardy, J., Hassanpour, A., Lai, X., Rehan, M., 2014. The influence of blending process on the quality 635
of rapeseed oil-used cooking oil biodiesels. J. Environ. Sci. 3, 233-240. 636
637
Hernandez, M.R., Gomez, A., Garcıa, A.N., Agullo, J., Marcilla, A., 2007. Effect of the temperature in 638
the nature and extension of the primary and secondary reactions in the thermal and HZSM-5 catalytic 639
pyrolysis of HDPE. Appl. Catal., A 103, 183-317. 640
641
Hu, Y., Li, S., 2007. The effects of magnesium hydroxide on flash pyrolysis of polystyrene. J. Anal. 642
Appl. Pyrolysis 78, 32-39. 643
20
Islam, M.R., Parveen, M., Haniu, H., Sarker, M.I., 2010. Innovation in pyrolysis technology for 644
management of scrap tire: a solution of energy and environment. Int. J. Environ. Sci. Dev. 1, 89-96. 645
646
Jindaporn, J., Lertsatitthanakorn, C., 2014. Characterization and utilization of char derived from fast 647
pyrolysis of plastic wastes. Procedia Eng. 69, 1437-1442. 648
649
Jung, S.H., Kim, S.J., Kim, J.S., 2013. The influence of reaction parameters on characteristics of 650
pyrolysis oils from waste high impact polystyrene and acrylonitrile–butadiene–styrene using a fluidized 651
bed reactor. Fuel Process. Technol. 116, 123-129. 652
653
Karaduman, A., 2002. Pyrolysis of polystyrene plastic wastes with some organic compounds for 654
enhancing styrene yield. Energy Sources 24, 667-674. 655
656
Kartal, S.N., Terzi, E., Kose, C., Hofmeyr, J., Imamura, Y., 2011. Efficacy of tar oil recovered during 657
slow pyrolysis of macadamia nut shells. Int. Biodeterior. Biodegrad. 65, 369-373. 658
659
Kim, J.R., Yoon, J.H., Park, D.W., 2002. Catalytic recycling of the mixture of polypropylene and 660
polystyrene. Polym. Degrad. Stab. 76, 61-67. 661
662
Kobayashi, T., Kuramochi, H., Xu, K.Q., 2016. Variable oil properties and biomethane production of 663
grease trap waste derived from different resources. Int. Biodeterior. Biodegrad. Doi:10.1016/j.ibiod. 664
2016.07.001. 665
666
Kumara, S., Prakashb, R., Muruganb, S., Singha, R.K., 2013. Performance and emission analysis of 667
blends of waste plastic oil obtained by catalytic pyrolysis of waste HDPE with diesel in a CI engine. 668
Energy Convers. Manage. 74, 323-331. 669
670
Lam, S.S., Liew, R.K., Lim, X.Y., Ani, F.N., Jusoh, A., 2016. Fruit waste as feedstock for recovery by 671
pyrolysis technique. Int. Biodeterior. Biodegrad. 113, 325-333. 672
673
Lee, S.Y., Yoon, J.H., Kim, J.R., Park, D.W., 2002. Degradation of polystyrene using clinoptilolite 674
catalysts. J. Anal. Appl. Pyrolysis 64, 71-83. 675
676
Lee, C.G., Kim, J.S., Song, P.S., Choi, G.S., Kang, Y., Choi, M.J., 2003. Decomposition characteristics 677
of residue from the pyrolysis of polystyrene waste in a fluidized-bed reactor. Korean J. Chem. Eng. 20, 678
133-137. 679
21
Lee, S., Yoshida, K., Yoshikawa, K., 2015. Application of waste plastic pyrolysis oil in a direct injection 680
diesel engine: for a small scale non-grid electrification. Energy Environ. Res. 5, 18-32. 681
682
Li, H., Xia, S., Ma, P., 2016. Upgrading fast pyrolysis oil: Solvent–anti-solvent extraction and blending 683
with diesel. Energy Convers. Manage. 110, 378-385. 684
685
Lopez, A., Marco, D.L., Caballero, B.M., Laresgoiti, M.F., Adrados, A., 2011. Influence of time and 686
temperature on pyrolysis of plastic wastes in a semi-batch reactor. Chem. Eng. J. 173, 62-71. 687
688
Lopez, A., Marco, I.D., Caballero, B.M., Laresgoiti, M.F., Adrados, A., 2012. Catalytic stepwise 689
pyrolysis of packaging plastic waste. J. Anal. Appl. Pyrolysis 96, 54-62. 690
691
Madon, R.J., 1991. Role of ZSM-5 and ultrastable Y zeolites for increasing gasoline octane number. J. 692
Catal. 129, 275-287. 693
694
Miandad, R., Rehan, M., Ouda, O.K.M., Khan, M.Z., Ismail, I.M.I., Shahzad, K., Nizami, A.S., 2016a. 695
Waste-to-hydrogen energy in Saudi Arabia: challenges and perspectives. In book, ‘biohydrogen 696
production: sustainability of current technology and future perspective’. Springer India. http://dx.doi. 697
org/10.1007/978-81-322-3577-4_11. 698
699
Miandad, R., Barakat, M.A., Aburiazaiza, A.S., Rehan, M., Nizami, A.S., 2016b. Catalytic pyrolysis of 700
plastic waste: a review. Process Saf. Environ. Prot. 102, 822–838. 701
702
Miandad, R., Barakat, M., Rehan, M., Ismail, I.M.I., Nizami, A.S., 2016c. The energy and value-added 703
products from pyrolysis of waste plastics. In book, ‘Recycling of solid waste for biofuels and bio-704
chemicals’ under series title: environmental footprints and eco-design of products and processes. 705
Springer Science+Business Media, Singapore. http://dx.doi.org/10.1007/978-981-10-0150-5_12. 706
707
Miandad, R., Nizami, A.S., Rehan, M., Barakat, M., Khan, M.I., Mustafa, A., Ismail, I.M.I., Murphy, 708
J.D., 2016d. Influence of temperature and reaction time on the conversion of polystyrene waste to 709
pyrolysis liquid oil. Waste Manage. http://dx.doi.org/10.1016/j.wasman.2016.09.023. 710
711
Miandad, R., Barakat, M.A., Aburiazaiza, A.S., Rehan, M., Ismail, I.M.I., Nizami, A.S., 2016e. Effect 712
of plastic waste types on pyrolysis liquid oil. Int. Biodeterior. Biodegrad. http://dx.doi.org/10.1016/j. 713
ibiod.2016.09.017. 714
715
22
Miskolczi, N., Angyal, A., Bartha, L., Valkai, I., 2009. Fuel by pyrolysis of waste plastics from 716
agricultural and packaging sectors in a pilot scale reactor. Fuel Process. Technol. 90, 1032-1040. 717
718
Mohebali, G., Ball, A.S., 2016. Biodesulfurization of diesel fuels – Past, present and future perspectives. 719
Int. Biodeterior. Biodegrad. 110, 163-180. 720
721
Mohammed, J., Nasri, N.S., Zaini, M.A.A., Hamza, U.D., Ani, F.N., 2015. Adsorption of benzene and 722
toluene onto KOH activated coconut shell based carbon treated with NH3. Int. Biodeterior. Biodegrad. 723
102, 245-255. 724
725
Munir, S., Habeebullah, T.M., Mohammed, A.M.F., Morsy, E.A., Rehan, M., Ali, K., 2016. Analysing 726
PM2.5 and its association with PM10 and meteorology in the arid climate of Makkah, Saudi Arabia. 727
Aerosol Air Qual. Res. doi: 10.4209/aaqr.2016.03.0117. 728
729
Nikodinovic-Runic, J., Casey, E., Duane, G.F., Mitic, D., Hume, A.R., Kenny, S.T., O’Connor, K.E., 730
2011. Process analysis of the conversion of styrene to biomass and medium chain length 731
polyhydroxyalkanoate in a two-phase bioreactor. Biotechnol. Bioeng. 108, 2447-2455. 732
733
Nileshkumar, K.D., Patel, T.M., Jani, R.J., Rathod, G.P., 2015. Effect of blend ratio of plastic pyrolysis 734
oil and diesel fuel on the performance of single cylinder CI engine. Int. J. Sci. Technol. Eng. 1, 195-735
203. 736
737
Nizami, A.S., Ismail, I.M.I., 2013. Life-cycle assessment of biomethane from lignocellulosic biomass. 738
Chapter in ‘Life cycle assessment of renewable energy sources’. Green energy and technology book 739
series. Doi: 10.1007/978-1-4471-5364-1_4. Publisher: Springer-Verlag London Ltd. 740
741
Nizami, A.S., Ouda, O.K.M., Rehan, M., El-Maghraby, A.M.O., Gardy, J., Hassanpour. A., 2016a. The 742
potential of Saudi Arabian natural zeolites in energy recovery technologies. Energy 108, 162-171. 743
744
Nizami, A.S., Shahzad, K., Rehan, M., Ouda, O.K.M., Khan, M.Z., Ismail, I.M.I., Almeelbi, T., 745
Demirbas, A., 2016b. Developing waste biorefinery in Makkah: a way forward to convert urban waste 746
into renewable energy. Appl. Energy http://dx.doi.org/10.1016/j.apenergy.2016.04.116. 747
748
Nizami, A.S., 2015. How can we achieve sustainability in our environment utilizing indigenous 749
knowledge? Int. J. Agric. Environ. Res. 1, 18-29. 750
751
23
Nizami, A.S., Rehan, M., Ismail, I.M.I., Almeelbi, T., Ouda, O.K.M., 2015a. Waste biorefinery in 752
Makkah: a solution to convert waste produced during hajj and umrah seasons into wealth. Conference: 753
15th scientific symposium for hajj, umrah and Madinah visit. Held in May 2015 in Madinah, Saudi 754
Arabia. 755
756
Nizami, A.S., Rehan, M., Ouda, O.K.M., Shahzad, K., Sadef, Y., Iqbal, T., Ismail, I.M.I., 2015b. An 757
argument for developing waste-to-energy technologies in Saudi Arabia. Chem. Eng. Trans. 45, 337-758
342. 759
760
Onwaduili, J.A., Insura, N., Williams, P.T., 2009. Composition of products from the pyrolysis of 761
polyethylene and polystyrene in a closed batch reactor: Effects of temperature and residence time. J. 762
Anal. Appl. Pyrolysis 86, 293-303. 763
764
Orgchem. Table of characteristics IR absorptions. 2015. Available: http://orgchem.colorado.edu/ 765
Spectroscopy/specttutor/irchart.pdf. 766
767
Ouda, O.K.M., Raza, S.A., Nizami, A.S., Rehan, M., Al-Waked, R., Korres, N.E., 2016. Waste to 768
energy potential: a case study of Saudi Arabia. Renew. Sustain. Energy Rev. 61, 328-340. 769
770
Pavia, D.L., Lampman, G.M., Kriz, G.S., Vyvyan, J.A., 2009. Introduction to spectroscopy (4th ed.), 771
Cengage Learning, California, pp. 15-104. 772
773
Qin, G., Gong, D., Fan, M., 2013. Bioremediation of petroleum-contaminated soil by biostimulation 774
amended with biochar. Int. Biodeterior. Biodegrad. 85, 150-155. 775
776
Rahmanian, N., Ali, S.H.B., Homayoonfard, M., Ali, N.J., Rehan, M., Sadef, Y., Nizami, A.S., 2015. 777
Analysis of physiochemical parameters to evaluate the drinking water quality in the State of Perak, 778
Malaysia. J. Chem. vol. 2015, Article ID 716125, 1-10. 779
780
Ramli, A., Bakar, A., Ratnasari, D., 2011. Effect of calcination method on the catalytic degradation of 781
polystyrene using Al2O3 supported Sn and Cd catalysts. J. Appl. Sci. 11, 1346-1350. 782
783
Rathore, D., Nizami, A.S., Pant, D., Singh, A., 2016. Key issues in estimating energy and greenhouse 784
gas savings of biofuels: challenges and perspectives. Biofuel Res. J. 10, 380-393. 785
786
24
Rehan, M., Kale, G.M., Lai, X., 2015. An in situ EDXRD kinetic and mechanistic study of the 787
hydrothermal crystallization of TiO2 nanoparticles from nitric acid peptized sol–gel. Cryst. Eng. Comm. 788
17, 2013-2020. 789
790
Rehan, M., Lai, X., Kale, G.M., 2011. Hydrothermal synthesis of titanium dioxide nanoparticles studied 791
employing in situ energy dispersive X-ray diffraction. Cryst. Eng. Comm. 13, 3725-3732. 792
793
Rehan, M., Nizami, A.S., Shahzad, K., Ouda, O.K.M., Ismail, I.M.I., Almeelbi, T., Iqbal, T., Demirbas, 794
A., 2016. Pyrolytic liquid fuel: A source of renewable electricity generation in Makkah. Energy Sources 795
Part A. 38, 2598-2603. 796
797
Sadef, Y., Nizami, A.S., Batool, S.A., Chaudhary, M.N., Ouda, O.K.M., Asam, Z.Z., Habib, K., Rehan, 798
M., Demirbas, A., 2016. Waste-to-energy and recycling value for developing integrated solid waste 799
management plan in Lahore. Energy Sources Part B. 11, 569-579. 800
801
Saptoadi, H., Pratama, N.N., 2015. Utilization of plastics waste oil as partial substitute for kerosene in 802
pressurized cookstoves. Int. J. Environ. Sci. Dev. 6, 363-371. 803
804
Seo, Y.H., Lee, K.H., Shin, D.H., 2003. Investigation of catalytic degradation of high density, 805
polyethylene by hydrocarbon group type analysis. J. Anal. Appl. Pyrolysis 70, 383-98. 806
807
Shah, J., Jan, M.R., 2014. Conversion of waste polystyrene through catalytic degradation into valuable 808
products. Korean J. Chem. Eng. 31, 1389-1398. 809
810
Sharma, B.K., Moser, B.R., Vermillion, K.E., Doll, K.M., Rajagopalan, N., 2014. Production, 811
characterization and fuel properties of alternative diesel fuel from pyrolysis of waste plastic grocery 812
bags. Fuel Process. Technol. 122, 79-90. 813
814
Shahzad, K., Rehan, M., Ismail, I.M.I., Sagir, M., Tahir, M.S., Bertok, B., Nizami, A.S., 2015. 815
Comparative life cycle analysis of different lighting devices. Chem. Eng. Trans. 45, 631-636. 816
817
Sharuddin, S.D.A., Abnisa, F., Daud, W.M.A.W., Aroua, M.K., 2016. A review on pyrolysis of plastic 818
wastes. Energy Convers. Manage. 115, 308-326. 819
820
Siddiqui, M.N., Redhwi, H.H., 2009. Pyrolysis of mixed plastic for recovery of useful products. Fuel 821
Process. Technol. 90, 545-552. 822
25
Singh, A., Pant, D., Korres, N.E., Nizami, A.S., Prasad, S., Murphy, J.D., 2010. Key issues in life cycle 823
assessment of ethanol production from lignocellulosic biomass: Challenges and perspectives. 824
Bioresource Technol. 10, 5003-5012. 825
826
Sriningsih, W., Saerodji, M.G., Trisunaryanti W., Triyono, A.R., Falah. I.I., 2014. Fuel production from 827
LDPE plastic waste over natural zeolite supported Ni, Ni-Mo, Co and Co-Mo. Procedia Environ. Sci. 828
20, 215-224. 829
830
Syamsiro, M., Saptoadi, H., Norsujianto, T., Noviasri, C.S., Alimuddin, Z., Yoshikawa, K., 2014. Fuel 831
oil production from municipal plastic wastes in sequential pyrolysis and catalytic reforming reactors. 832
Energy Procedia 47, 180-188. 833
834
Ukei, H., Hirose, T., Horikawa, S., Takai, Y., Taka, M., Azuma, N., 2000. Catalytic degradation of 835
polystyrene into styrene and a design of recyclable polystyrene with dispersed catalysts. Catal. Today 836
62, 67-75. 837
838
Walendziewski, J., Steininger, M., 2001. Thermal and catalytic conversion of waste polyolefins. Catal. 839
Today 65, 323-330. 840
841
Williams, P.T., Bagri, R., 2004. Hydrocarbon gases and oils from the recycling of polystyrene waste by 842
catalytic pyrolysis. Int. J. Energy Res. 28, 31-44. 843
844
Wongkhorsub, C., Chindaprasert, N., 2013. A comparison of the use of pyrolysis oils in diesel engine. 845
Energy. Power Eng. 5, 350-355. 846
847
Zeaiter, J., 2014. A process study on the pyrolysis of waste polyethylene. Fuel 133, 276-282. 848
849
Zeolyst. Zeolite Y type products. CBV 780. Zeolyst International 2015. Available: http://www.zeolyst. 850
com/our-products/standard-zeolite-powders/zeolite-y.aspx. 851
852
Zhang, J.H., Wang, Z.B., Zhao, H., Tian, Y.Y., Shan, H.H., Yang, C.H., 2015. Multi-scale CFD 853
simulation of hydrodynamics and cracking reactions in fixed fluidized bed reactors. Appl. Petrochem. 854
Res. 5, 255-261. 855
856
26
857
Figure 1. Small pilot scale pyrolysis reactor (Miandad et al., 2016d). 858
859
860
Catalyst Chamber
Condenser Unit
Control Panel
Water Chiller
Oil Tank
Pyrolysis
27
861
862
863
Figure 2. SEM images of the Saudi Arabian natural zeolites. 864
865
28
866
867
868
869
870
871
872
873
874
875
876
Figure 3. SEM-EDXS of Saudi Arabian natural zeolite showing elemental composition and 877
quantities in wt% for certain location (Spectrum 4). 878
879
Element Wt% Wt% Sigma
O 57.2 0.24
Na 2.2 0.08
Mg 0.6 0.06
Al 7.0 0.10
Si 26.7 0.18
S 0.4 0.05
K 2.7 0.08
Ca 0.4 0.06
Ti 0.2 0.07
Fe 2.5 0.15
Total: 100.0
29
880
Figure 4. The yield of liquid oils, gases and char from thermal and catalytic pyrolysis with 881
natural and synthetic zeolite. 882
883
Thermal pyrolysisCatalytic pyrolysis
with natural zeolite
Catalytic pyrolysis
with synthetic zeolite
80.8%
54%50%
0
10
20
30
40
50
60
70
80
90
100
Thermal (No catalyst) Catalytic (Natural
Zeolite)
Catalytic (Synthetic
Zeolite)
Yie
ld (
%)
13% 12.8%
22.6%
0
10
20
30
40
50
60
70
80
90
100
Thermal (No catalyst) Catalytic (Natural
Zeolite)
Catalytic (Synthetic
Zeolite)
Yie
ld (
%)
Liquid oil yield
6.2%
32.8%27.4%
0
10
20
30
40
50
60
70
80
90
100
Yie
ld (
%)
Thermal pyrolysis Catalytic pyrolysis
with natural zeolite
Catalytic pyrolysis
with synthetic zeolite
Gases yield
Char
30
884 885
886
Figure 5. Reaction of polystyrene plastic waste with synthetic zeolite 887
31
888
889
Figure 6. FT-IR spectrum of PS plastic raw material and thermal and catalytic pyrolysis liquid 890
oils. 891
892
400 800 1200 1600 2000 2400 2800 3200
Tra
nsm
itta
nce
%
Wavenumbers (cm-1)
PS Feedstock Thermal Pyrolysis Natural Zeolites Pyrolysis Synthetic Zeolite Pyrolysis
Frequency cm-1 Bond Functional group 3020, 3030, 3070 =C-H stretch Aromatics 2850, 2920, 2940 C-H stretch Alkanes 1450, 1490 C-C stretch (in-ring) Aromatics 905, 989 =C-H bend Alkenes 697, 775 C-H “oop” Aromatics 533.71 C-Br stretch Alkyl halides
32
893
894
Figure 7. GC-MS analysis showing the effect of thermal and catalytic pyrolysis on liquid oil 895
60.8
10.7
4.82.5 1.3
0
10
20
30
40
50
60
70
Styrene Methylstyrene Azulene 1H-Indene Ethylbenzene
Catalytic pyrolysis with natural zeolite
0
5
10
15
20
25
30
35
40
9.9
15.8 16.3
4.2 3.5
8.1
38.4
48.3
21.2
25.6
1.6
0
10
20
30
40
50
60
Styrene Ethylbenzene Toluene Benzo (b) tri
phenylene
Thermal (non-catalytic)
Catalytic pyrolysis with synthetic zeolite
Wt%
Wt%
Wt%
33
896
897
Figure 8. Recovery of petroleum based plastics into gasoline range hydrocarbons 898
899
900
Petroleum based plastics
(domestic, commercial or
industrial source)
Collection and sorting
facility
(screening suitable plastics)
Pre-treatments
(size reduction, moisture,
contaminants removal etc.)
Pyrolysis
(thermal or catalytic
pyrolysis
Liquid fuel
production
Post-treatments
(removal of solid residue, acid,
impurities, chlorine etc. and
neutralization)
Fuel upgrading
(refining, blending,
purification)
Gasoline range
hydrocarbons
34
Table 1. Technical and economical comparison of pyrolysis with others WTE technologies (Ouda et 901
al., 2016a, Nizami et al., 2015c; Sadef et al., 2016; Rahmanian et al., 2015; Eqani et al., 2016; Munir 902
et al., 2016) 903
WTE technologi
es
Capital cost/
ton/year
Net operational cost /ton
Merits Limitations
Incineration
$14.5-$22 $1.5-$2.5
- Up to 80% of volume reduction
- Up to 70% of mass reduction
- Large amounts of waste can be treated
- Fast treatment
- Air and water pollution
- Carcinogenic chemical (dioxins) release
- Public opposition - Produce solid
waste (slag)
Pyrolysis $17-$25 $2-$3
- Up to 80% energy recovery from waste
- Reduced land requirement
- High calorific value products
- Liquid products easily separated from vapor phase
- Up to 50-90% reduction in MSW volume
- Lower liquid products yields
- Moisture produced from organic matter
- Coke formation from liquid products
- By-products cleaning
- Corrosion of pyrolysis metal tubes
Plasma arc gasificatio
n $19.5-$30 $2.5-$4
- No GHG emissions - All waste types can
be treated - Easy technology
expansion
- Higher energy consumption
- High capital and operating cost
Refuse derived
fuel (RDF) $7.5-$11.3 $0.3-$0.6
- Stabilized waste - Reduced waste
volume - RDF pellets having
high calorific values
- Air pollution by RDF fuel
- Ash formation - Land requirement
Anaerobic digestion
(AD) $0.1-$0.14 Minimal
- Lower solid produced
- High rate anaerobic composting with energy
- Nutrient rich digestate as an organic fertilizer
- Cost effective technology
- Impurities - Not suitable at
larger scale - Vulnerability to
overloads and shocks
- Space requirement
904 905
906
35
Table 2. Comparison of thermal and catalytic pyrolysis and their impacts on fuel characteristics 907
Thermal pyrolysis Catalytic pyrolysis Impact on fuel
Classification Classification is simple Technology classification is unclear
Poor market acceptance
Temperature High temperature demand leads to production of some diolefins
Decomposition of feedstock at low temperature
Effect fuel cost on product selectivity
Reaction time
High reaction time Low reaction time is required Effect on fuel cost
Gas formation
Increase production of CH4 and C2H6
Increase the concentration of C3 and C4 hydrocarbons
Effect the quantity and quality of gas production
Solid residue High solid residue production
Less solid residue production Effect the quality and quantity of oil
Impurities High impurities in the form of S, N, P, and acid
Impurities removed via adsorption
Effect on the quality of liquid oil
Aromaticity Less aromatic hydrocarbon formation
High aromatic hydrocarbon formation
Aromatic cyclization
Paraffins formation
Less formation of paraffin Paraffin production via hydrogen transfer
Effect on the gasoline selectivity
Reactivity Less reactivity More reactive especially for larger molecules
Effect on radical formation
Distribution of molecular weight
Large distribution of hydrocarbon with less short chain hydrocarbon
High production of short chain hydrocarbons
Effect on gasoline selectivity
908
909
910
911
912
913
914
915
916
917
918
919
920
921
36
Table 3. Pyrolysis reactor features 922 923
Heating tank (height) 360 mm Heating tank (diameter) 310 mm Catalytic chamber (height) 200 mm Catalytic chamber (diameter) 165 mm Reactor (total capacity) 20 L Catalytic chamber (total capacity) 1 L Condenser (length) 860 mm Condenser (diameter) 147 mm Temperature (maximum) 600 Ԩ
924
925
926
37
Table 4. Pyrolysis products yield and liquid oil composition of thermal and catalytic pyrolysis 927
928
Pyrolysis type Pyrolysis products (%) Liquid oil Liquid oil Gases Char (Composition %)
Thermal pyrolysis 80.8 13 6.2 Styrene (48.3) Ethylbenzene (21.2) Toluene (25.6) Benzo (b) tri phenylene (1.6)
Catalytic pyrolysis (natural zeolite)
54
12.8
32.8
Styrene (60.8) Methylstyrene (10.7) Azulene (4.8) 1H-Indene (2.5) Ethylbenzene (1.3)
Catalytic pyrolysis (synthetic zeolite)
50
22.6
27.4
Ethylbenzene (9.9) Styrene (15.8) Benzene (16.3) Propenylbenzene (4.2) Propylbenzene (3.5) Isopropylbenzene (8.1) Alpha-Methylstyrene (38.4)
38
Table 5. Higher heating value (HHV) in MJ/kg of the feedstock and produced liquid oil and 929
char 930
Feedstock (PS plastic)
Thermal pyrolysis Catalytic pyrolysis
Natural zeolite Synthetic zeolite Liquid Char Liquid Char Liquid Char 39.3 41.6 20.1 41.7 11.1 40.6 9.7
931
932
39
Table 6: Comparison of present study liquid oil with conventional diesel 933
Parameters
Our results
Conventional diesel
Reference
Dynamic viscosity (mPa.s)
1.8 1-4.1 Wongkhorsub and Chindaprasert, 2013
Density@15 °C (g/cm3)
0.9 0.8-0.9 Syamsiro et al., 2014
Kinematic viscosity @40 °C (cSt)
1.9 2.0-5.0 Syamsiro et al., 2014
Pour point (°C) -60 Max 18 Syamsiro et al., 2014 Flash point (°C) 30.2 Min 55-60 Syamsiro et al., 2014
934
935
936
40
Table 7. Heating value of different fuel types according to their hydrocarbon chains (Lee et al., 937
2015). 938
Fuel type Hydrocarbons HHV (MJ/kg) LPG C3 - C4 46.1 Petrol C4 - C12 44.0 Kerosene C12 - C15 43.4 Diesel C12 - C24 43.0 Heavy fuel oil C12 - C70 41.1
939
940
